Late summer nitrogen applications to pastures – will they pay in 2014?

We are close to the point where some livestock farmers would normally start to apply nitrogen to tall fescue pastures to boost production levels and stockpile for fall and winter grazing. Since there are many factors that will impact the profitability of this practice, the question at hand is: Under what set of conditions will applying nitrogen to pastures pay this year?

Soil moisture conditions are extremely variable throughout the state right now, with some areas having good to excellent soil moisture and other areas in moderate drought. There are lots of reports of soil moisture conditions changing from good to bad in as little as a five mile distance all through the state. Areas with good soil moisture will have the best response to nitrogen applications.

The price of nitrogen was evaluated on an elemental basis between .55-.75 cents per unit ($370-500 per ton ammonium nitrate and $505-690 per ton urea with urease inhibitor), with application rates of 40 and 80 units/acre. Three response rates (low, medium, and high) were evaluated corresponding to various soil moisture and fertility conditions.

Farm size and management practices were assumed to be typical Kentucky conditions: 30 cow herd with late winter/early spring calving. Waste rates were estimated at 25 percent for both hay feeding and grazing. Forage quality was estimated at 55 percent TDN for hay and 65 percent for stockpiled fescue. Machinery and labor costs were estimated at .09 and .29 cents per cow-day for grazing and hay feeding respectively. P and K from the hay were assumed to be recycled back into pastures at a 50 percent rate at .40 cents per pound for P2O5 and .40 cents per pound for K2O.

Results: There appear to be good opportunities for profitable nitrogen applications in fescue stands with a low clover content (less than 15 percent) in areas with decent soil moisture conditions. Assuming a medium response rate and nitrogen priced at .65 cents per unit ($600/ton urea with urease inhibitor), hay prices at or above $60/ton generated moderate to high cost savings. With the low response rate, these stands generated low to moderate costs savings with hay priced at or above $80/ton. With a high response rate, these stands generated high cost savings with just about all combinations of nitrogen and hay prices.

Cost savings occurred less frequently in the mixed fescue-clover stands. With a medium response rate, hay prices needed to be at or above $100/ton to generate even low cost savings. With the high response rate, hay prices needed to be at least $80/ton to generate low cost savings. Additionally, any potential savings in the fescue-clover stands need to be balanced against the potential loss of clover due to N applications. As a consequence, it is advised to target pastures with the highest fescue content before considering nitrogen applications to these mixed fescue-clover stands.

In terms of current soil moisture conditions, this means that in areas with at least decent soil moisture conditions, mostly pure stands of fescue should provide good opportunities for applying nitrogen and stockpiling forage for late fall and winter grazing. In areas that are starting to fall into drought conditions, it is probably better to wait until mid-August to see if conditions improve.

As noted above, hay quality was assumed to be medium-quality, mixed hay with a 55 percent TDN. There is a lot of hay put up in Kentucky that has a much lower feed value. For each 5 percent reduction in TND (e.g. going from 55 percent to 50 percent ), add $6-9/acre in cost savings for 40 unit applications and $10-15/acre for 80 unit applications. Use the lower part of this range for the medium response rate and the higher part of this range for the high response rate.

For more detailed results, consult the publication “Profitability of Nitrogen Applications for Stockpiling Tall Fescue Pastures – 2014 Guide” that can be found at: http://www.ca.uky.edu/agecon/index.php?p=169.

From the Bell County Cooperative Extension Service.

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